Fix API tracker to use dynamic JVM version for --release flag

Author: simbo1905

json-java21-api-tracker/src/main/java/io/github/simbo1905/tracker/ApiTracker.java

@@ -331,12 +331,14 @@ static JsonObject extractApiFromSource(String sourceCode, String className) {
             addCommonStubs(compilationUnits);
 
             // Parse-only compilation with relaxed settings
+            // Use current JVM version for --release to support preview features
+            final var javaVersion = Runtime.version().feature();
             final var options = List.of(
                 "-proc:none",
                 "-XDignore.symbol.file",
                 "-Xlint:none",
                 "--enable-preview",
-                "--release", "24"
+                "--release", String.valueOf(javaVersion)
             );
 
             final var task = (JavacTask) compiler.getTask(